Thermal printer and drive system for controlling print ribbon velocity and tension
AssigneePrintronix, Inc.
InventorsGordon B. Barrus, Kevin P. Moore
Life of this patent
Estimating the term…
Abstract
A thermal printer having a supply of media with a rotatable platen on which the media is moved for printing by a thermal printing head. A supply spindle supplies print ribbon from a supply spool mounted thereon, and a take-up spindle takes up the used print ribbon on a take-up spool. The spindles are each driven by a motor and controlled by a controller which detects the Back EMF (BEMF) of the motors, and calculates the velocity of the spindles, spool, and print ribbon to control each motor based on the BEMF. The status of the print ribbon as to low condition, breaks, ribbon full and other monitoring functions can be provided to a remote host computer or other monitoring station.
Claims41
A thermal printer comprising:
- support for a spool of media;
- a platen on which said media can move;
- a print head in association with said platen for printing on said media;
- a rotatable print ribbon supply spindle for a print ribbon supply spool;
- a rotatable take-up spindle for taking up print ribbon and forming a take-up spool from said supply spool as it moves in association with said media between said platen and print head;
- a motor connected to said print ribbon supply spindle;
- a motor connected to said take-up spindle;
- and,
- a control means to provide movement of said print ribbon by controlling the movement of said motors,
- wherein said control means calculates a desired tension on said print ribbon from said supply spindle, and tension on print ribbon to said take-up spindle and adjusts their respective velocities.
A drive for a thermal printer print ribbon for printing on media comprising:
- a supply spindle for supporting a supply spool of print ribbon;
- a take-up spindle for supporting a take-up spool for print ribbon;
- a motor for driving said supply spindle;
- a motor for driving said take-up spindle;
- means for detecting the Back EMF (BEMF) on each motor;
- and,
- a controller for calculating the movement of each motor based upon the BEMF and controlling the print ribbon between said spools based upon the velocity.
A thermal printer comprising:
- means for supplying media;
- means for taking up media that has been printed upon;
- a rotatable platen on which said media passes and which causes said media to be moved for printing purposes;
- a thermal printer head;
- a supply spindle for supplying print ribbon from a supply spool of print ribbon mounted thereon;
- a take-up spindle for taking up print ribbon which has been used for printing said media and on which said print ribbon can be wound as a take-up spool;
- a supply spindle motor connected to said supply spindle;
- a take-up spindle motor connected to said take-up spindle;
- a controller connected to said motors;
- means for detecting the Back EMF (BEMF) of the supply spindle motor and take-up spindle motor;
- and,
- means in said controller for controlling and monitoring the print ribbon based upon the BEMF.
A method of controlling a thermal printer comprising:
- providing a supply spool of print ribbon mounted on a supply spindle;
- providing a take-up spindle for print ribbon on which a spool of print ribbon can be wound;
- providing a motor to said supply spindle and a motor to said take-up spindle;
- and,
- controlling and monitoring the print ribbon by the Back EMF (BEMF) of each motor.
A method of thermal printing comprising:
- providing a spool of media that is to be printed upon;
- moving said media over a rotating platen;
- supplying a spool of print ribbon from a supply spool;
- moving said print ribbon over said platen and said media for printing thereon;
- providing a take-up spool for taking up the print ribbon after printing has taken place;
- driving said supply spool with a D.C. motor;
- driving said take-up spool with a D.C. motor;
- and,
- controlling said supply spool D.C. motor and take-up spool D.C. motor for print ribbon movement between them by utilizing the Back EMF (BEMF) signals of said motors.
Dependencies are inferred from the claim text.